Grafting of immature plants has hitherto been developed by hand works of farmers. There are prepared stocks and scions, grafting parts of which are cut off by means a knife. Thereafter, the grafting parts are fixedly bundled with clips or strings and then employed as saplings after nurturing them.
In recent years, the number of agricultural workers who succeed to this grafting art has been decreased. Under such circumstances, grafting is in some cases performed by use of a robot or the like.
In the former conventional example, grafting is based entirely on the hand works which require a good deal of labors for manually cutting the stocks and scions and grafting them. In the latter case, the operations of men are merely replaced with mechanical operations.
For this reason, it is difficult to graft a tremendous number of saplings.
In the latter case, the worker performs the operation by recognizing a pattern while observing the saplings, If this operation is done by a computer-incorporated robot, there arise problems of requiring much time and expensive equipments. This leads to a rise in cost.
As prior art means for producing masses of grafting saplings, there are exemplified an apparatus for and a method of grafting immature plants, which involves the steps of seizing a plurality of saplings raised in array with a pair of seizing members, obtaining both stocks by cutting the saplings with upper portions of the seizing members and scions by cutting them with lower portions thereof while seizing them with the seizing members, superposing the scion on the stock, and thus grafting the two saplings.
The seizing tool employed in the prior art grafting apparatus is formed with semi-circular arc notches for seizing the stems of samplings.
The saplings seized by the seizing tool are singly cut off with an cutting edge like a razor.
The above-mentioned seizing tool is constructed to respectively seize the arrayed-saplings per line.
The seizing tool of the conventional apparatus for grafting the immature plants has such a restraint that the saplings raised in array have to be inserted one by one into the notches of the pair of seizing members of the seizing tool. If inserted, the sapling tends to come off while dealing with other saplings, which causes troublesomeness and requires labors for seizing the saplings. An additional operation required is to take countermeasures against a scatter in thickness of the stems which is due to differences between growth rates and forms by selecting the saplings adaptive to a predetermined diameter of the notch of the seizing tool and fostering the saplings till the stems adjust themselves to the notch diameter. This needs well-experienced techniques and knowledge. If the forms are different, and if the stems differ according to the times for grafting, a seizing tool has to be prepared according to the forms. When inserting the saplings into the notches of the seizing tool, the saplings are in some cases damaged, with the result that the samplings may probably be infected with diseases. The sapling stems are fixedly set in the notches each having the predetermined diameter, and hence deformations such as constrictions are produced in the stems according as the saplings grow. The deformed parts are stuck to the seizing members, which in turn leads to an easy-to-damage condition for the samplings.
Besides, the prior art grafting apparatus has drawbacks in which the saplings fostered in array in a sapling box are treated per line, whereby there are caused limits both to the number of saplings grafted en bloc and to a reduction in cost; and the grafting operations are sequentially carried out per sapling box, resulting in a probability that the saplings of the initially grafting line will have already drooped when grafting the saplings of the last line in the case of one-line-basis grafting. An additional drawback is that the saplings are to be damaged due to hindrance by samplings of the previous line.
Furthermore, it is difficult to operate the edge of the cutting tool adapted to the foregoing operations, and this causes a dangerous situation in which the fingers are to be hurt. In the case of a cutting tool with a shank, the shank impinges on other saplings and spoils them. The saplings are cut off by manually handling the cutting tool, and it follows that the operation becomes unstable. A fine cut face can not be obtained at one time. Besides, the cut face has to be confirmed each time, and a good deal of labors are required for such confirmations. A highly sophisticated technique is needed for obtaining the fine cut face, and it is difficult to cut the saplings catered for scions particularly with the lower portions of the seizing tool. The fact that it takes much time to cut the saplings presents a serious problem to the saplings for grafting which are fragile under a dried condition. This exerts great influences directly on a modulus of rootage and on a growth rate.